Question: What do the following two equations represent? $x+5y = 4$ $4x+20y = -1$
Answer: Putting the first equation in $y = mx + b$ form gives: $x+5y = 4$ $5y = -x+4$ $y = -\dfrac{1}{5}x + \dfrac{4}{5}$ Putting the second equation in $y = mx + b$ form gives: $4x+20y = -1$ $20y = -4x-1$ $y = -\dfrac{1}{5}x - \dfrac{1}{20}$ The slopes are equal, and the y-intercepts are different, so the lines are parallel.